Centrifugal self-priming pump



May 231, 1935.

H. E. RUFF Filed May 8, 1933 A TTORNEYS.

Patented May 21, 1935 UNITED STATES CENTRIFUGAL SELF-PRIMIN G PUMP Herbert E. Rupp,

Gorman-Rupp Comp corporation of Ohio Mansfield, Ohio, assignor to any, Mansfield, Ohio, at

Application May 8 1933, Serial No. 669,890

10 Claims. This invention aims to provide an improved centrifugal pump, embodying a novel principle and features of priming or repriming by means of a liquid chamber above the impeller chamber,

wherein the cooperative chambers and passages are so arranged in relation to each other that the customary recirculation of liquidfrom the discharge to the suction sideor an auxiliary evacuating means are eliminated.

Another important object is to produce a very simple form of pump wherein the liquid and impeller chambers may be of unit construction and the usual plurality of parts are reduced to a minimum. Strength and durability as Well as inexpense in manufacture are additional desiderata.

These and other objects are attained by the mechanism and means illustrated in the accompanying drawing, in which- Fig. 1 is a side elevation view of the pump represented partly in cross-section, and

Fig. 2 is a front sectional view on the line A--A of the first figure, showing the liquid chamber disposed directly over the impeller chamber.

Referring to said drawing, the pump body I has the customary impeller 2 mounted within the impeller chamber 3. This chamber has the customary cut-01f 4 arranged preferably in a vertical axis or plane in the sense that it is disposed above the level of the impeller, and said cut-off is the source of an annular outwardly diverging wall 5 which terminates at 6 in the form of a spiral or volute casing having no part above the outoff level. The space between 4 and 6 provides a communicating passage 1 (opposite the bottom 8) between the impeller chamber (3) which forms the lower portion of the pump body and the liquid chamber 9 which forms the upper portion of said body.

The aforesaid liquid chamber has two-openings Ill and H at its top, one of which, being ID in this instance, is used for the discharge from the pump. The other of these openings, being I I in this instance, is then fitted with a plug Ha or some other means of closure.

The back E2 of the impeller chamber has an associated upward extending suction passage I 3 which turns outward to the horizontal at its upper end and has an opening face so inclined that gravity tends to keep a flap valve I4 on its seat l5 formed by the flange face of the suction connection plate Hi.

The pump thus formed is adapted to be filled with liquid to the top, since the flap-valve (I 4) lying against its seat prevents any drainage through the intake opening and there are no leak points elsewhere. This is done of course through the free one of the aforementioned top openings by removing the plug Ila therefrom when first starting the pump in operation, and some of the 5 liquid to be pumped may be used for the purpose.

To operate, the pump first filled with liquid is started by setting the impeller into rotation. This impeller is of conventional type either open or closed, comprising a plurality of backward sloping vanes preferably overlapping one another and is mounted upon a shaft ll passing through a studing box l8 and driven by any desired power means. It will be apparent that as said impeller is rotated, the liquid within or between its vanes will be forced outward by centrifugal force into the chamber above and that the liquid within the passage l3 will be simultaneously drawn into the impeller and likewise expelled thereby into-said chamber. The air or gas standing in the suction line (not shown) connected to the flange IE will then be drawn into the impeller chamber by the partial vacuum thus created therein, and said impeller next quickly expunges-this air or gas to create a suction strong enough to draw the liquid up from the pumping source into the pump. The action by which this is done is as follows:

The continuing rotation of the impeller with its backward sloped vanes, illustrated by l9 and 20, whirling at fast speed under the body of the liquid in the chamber thereover sustains and holds said liquid body within said chamber under a resilient tension seeking to gravitate back into the lower chamber but prevented from so doing by the propelling force of the vanes. The liquid is thus kept agitated and pulsating at the opening (1) by the vanes successively passing thereunder, with each vane driving or pushing it upward while moving across said opening, before it can advance backwardly therethrough. Now the air or gas drawn into the impeller chamber as the latter is liquidevacuated is expelled off by the centrifugal force of the impeller in the same way or in the fashion of a blower. It cannot escape through the encasing wall and there is no space above the 4 impeller where it can be trapped to avoid expulsion and so defeat the pump priming. It therefore expunges through the only possible outlet, i. e. the aforesaid opening (1) between the points 4 and 6 which is sealed over by the liquid body. This it does by discharging portions into pockets of the liquid caused by the agitation of the latter as each vane passes thereunder until all of the air or gas has been driven out. In other words, the air is simply exhausted by degrees into and through the liquid body kept in constant agitation suflicient to receive it, and passingupward in bubble form, expels through the discharge line (not shown) or port.

This is the natural result of the centrifugal force, any air or gas within the impeller being carried around thereby until received into the liquid by its driving force. Simultaneously drawing the air or gas thereto from the suction line, the impeller quickly evacuates the latter and sets up a strong suction in the pump, while the liquid body above the impeller forms a "seal preventing air being drawn in from the outside. It will be noted that there is no re-circulation of liquid through or in the impeller chamber during this priming action or at any other time in the pump operation. 7

Due to the momentum which the volume of liquid and gases receives while being discharged by the rapidly rotating impeller, such liquid and gases move upward toward the wall 25 of the upper chamber as indicated by the arrows. The lower curved portion 26 of said wall aids to direct this upward movement and the body of liquid within said chamber being relatively large in proportion to the discharges from the impeller chamber, all gases pass accelerantly to the top and there expel through the discharge opening Ill. The successive vane movements past the cutoff opening (1) of course maintain this effect .until all gas or air is exhausted from the pump to prime it and establish the suction necessary to draw the liquid up from the pumping source. From then on the impeller sucks and discharges the liquid as any ordinary centrifugal pump.

It should here be remarked that when the pump is pumping, the discharge from the impeller chamber into the liquid chamber along the bottom of the latter keeps the liquid within said liquid chamber constantly and violently swirled, so that all dbris and the like will be kept in suspension within the moving liquid. Consequently, the liquid chamber is kept always free from any lodged dbris and such as may be pumped up, together with mud and silt is forced out with the liquid through the discharge opening l0.

Should the pump exhaust down to its suction line inlet or otherwise take in a volume of air, thereby breaking its prime, the above described process of priming or expelling the air is repeated until it is again ready to pump, whereupon operation is resumed as before.

I am aware that there are pumps having various chambers and various impellers including those with backward sloping vanes. All such pumps, however, require auxiliary by-pass channels and other mechanisms to attain their intended results. Anyone familiar with the art will readily recognize that the relation of component parts in my pump is such that auxiliary passages and the usual control devices therefore as well as all other mechanical contraptions are entirely eliminated. Consequently there is nothing in my pump to become fouled when pumping liquids containing dbris and the like, while the pump is of the simplest possible form and construction.

In the latter connection it may be remarked that owing to the inertia of the liquid, it is essential for the two chambers to be as close together as it is possible to bring them and in construction therefore, these chambers are practically blended one into the other, so that the partial vacuum within the impeller will have the desired effect of pulling the liquid down with gravity aid as the impeller vanes successively pass the communicative opening (1). In actual practice this pump has raised water 28 feet with an impeller 7%, inches in diameter, turning at 1800 R. P. M. and having only two vanes as here shown. A greater number of vanes however is generally preferable.

Should the pump be stopped at any time, the flap valve (I4) will drop down upon its seat (l5) and retain the liquid in the pump indefinitely for successive starting. It is therefore unnecessary to refill the chamber after every stop. The pump has the further advantage that it is cheaper and more easily manufactured than more complicated pumps of the same class.

The non-recirculating pump thus provided is not only extremely simple and light, but it operates with great eillciency at low horsepower and operating costs, and may be smaller than other pumps of the same capacity. The absence of wearing and control parts eliminates necessity of replacements .and constant attention to keep it in operation. It has a larger volume discharge and will pump from and to higher levels than ordinary recirculating pumps. It will also hold the prime in its suction line for an indefinite time because the liquid therein cannot siphon or drain out when the driving engine is stopped. One of its chief advantages is that at higher pressure heads, its volume output and efliciency is increased proportionately, whereas a recirculating pump loses volume and efliciency in proportion to pressure at high heads.

' Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A self-priming centrifugal pump, comprising, a volute impeller casing, a rotary impeller therein formed with backwardly sloping blades, a liquid retaining chamber over said impeller chamher, and a communicating passage between the two chambers formed by the volute of the firstnamed chamber opening into the bottom of the second-named chamber over the impeller and substantially in vertical line with the axis thereof; the side of said passage nearest to the impeller providing therewith a cut-off for liquid flow in the direction of impeller rotation.

2. In a centrifugal self-priming pump, an impeller chamber of volute form, a rotary impeller therein having backwardly sloping vanes and a liquid retaining chamber directly over said impeller chamber; the volute discharge of the impeller chamber opening into the bottom of the retaining chamber in a substantially horizontal plane over said impeller so as to provide a communicating passage between the two chambers substantially in a vertical plane with the impeller axis, and the beginning of said volute together with the impeller providing a cut-01f for liquid from the retaining chamber.

3. A self-priming centrifugal pump comprising a volute impeller casing, a rotary impeller therein formed with backwardly sloping vanes, a liquid retaining chamber over said impeller chamber and a communicating passage between the two chambers formed by the volute of the first named chamber opening into the bottom of the second named chamber over said impeller in substantially vertical line with its axis, one side of said passage providing a cut-off of liquid flow into the impeller casing in the direction of impeller rotation.

4. A self-priming centrifugal pump comprising a volute impeller chamber, a rotary impeller therein, a liquid retaining chamber above the impeller chamber and a single communicating passage between the two chambers opening from the lower chamber in the plane of said impeller over the upper quadrant of the same adjacent its point of peripheral proximity to the surrounding chamber wall; one side of said passage to- 5. A non-recirculating self-priming centrifugal pump, comprising, a volute impeller chamber, a rotary impeller therein formed with backwardly curved blades, a liquid retaining chamber located directly over said impeller chamber, and a single communicating passage between the two cham-' bers formed by the volute mouth of the firstnamed chamber opening into the bottom of the second-named chamber over the upper part 01 said impeller so as to include a vertical plane through its axis; said impeller being so disposed in its chamber that no space for entrapment of air is left thereabove and its blades sweep close enough to one edge of said opening to therewith provide a cut-oil for liquid which might otherwise enter in its direction of rotation from the chamber above.

6. A self-priming centrifugal pump, comprising, a volute impeller chamber, a rotary impeller therein having backwardly sloping blades and associated means for driving it at high speed, a liquid retaining chamber directly over the impeller chamber and a communicating passage between the two chambers opening directly from the lower chamber into the upper chamber over the upper quadrant of said impeller adjacent a point of the latters peripheral proximity to its surrounding chamber wall and together with said impeller forming a liquid cut-off, whereby liquid from the retaining chamber will not enter the impeller chamber in the direction of impeller rotation during rotation of the same but will tend to enter said impeller chamber against the impeller in a direction opposite to its rotation.

7. A self-priming centrifugal pump embodying a volute rotor-pump casing having a driven rotary impeller therein formed with backward sloping blades, a liquid retaining chamber thereabove, and a single conmiunicating passage between said casing and chamber formed by the volute of the former opening into the bottom or the latter; said opening being directly over with the impeller providing a cut-oi! for liquid entering therethrough from the chamber above in the direction of impeller rotation during rotation oi. the same, said impeller being so disposed in its casing that no space is left for the entrapment of, air thereabove and the upper portion of the impeller is exposed thro gh said fi nsto the body of liquid in the chamber a ve.

8. A non-recirculating self-priming centriiugal pump, comprising, a volute impeller chamber having chamber over the impeller chamber, a single communicating passage between the two chambers disposed intermediate the sides thereof with respect to the plane of impeller rotation therein, and a rotary impeller in said impeller chamber having backwardly curving blades arranged to pass close to one side of the passage and therewith provide a liquid cut-ofl from the upper to the lower chamber.

9, A non-recirculating self-priming centrifugal pump, comprising, a volute rotor-pump casing having an inlet port, a liquid retaining chamber over said casing, a single communicating passage between the casing and said chamber opening direct from the top of the former into the bottom of the latter and disposed intermediate the sides of said casing with respect to the plane of impeller rotation therein, and a rotary impeller having backwardly curving blades mounted in said casing to pass close to one side of the passage and therewith provide a liquid cut-cit from the upper chamber to the lower casing in the direction of impeller rotation.

10. In a self-priming centrifugal pump including a volute impeller casing having an inlet passage, a rotary impeller therein having backwardby curving blades and associated means for driving the same at high speed, a liquid retaining chamber over the casing having an outlet passage, and a communicating passage between the casing and chamber formed by the mouth of the volute opening into the bottom of the chamber and located over the impeller axis with one side close to the periphery of the impeller so that liquid in the chamber will therethrough be subjected to the action of said impeller without reentering the casing in the direction of impeller rotation during operation of the same; said communicating passage comprising the only communication between said casing and said chamber.

' HERBERT E. RUPP.

an intake port, a liquid retaining vcmmncxm or oomcmo'u.

Patent No. 2,002,454. w 21, 1955.

HERBERT E. RUPP.

Itis hereby certified that errorappeare in the above numbered. patent requiring correction as follows: 'In the drawing, Figure 1, for the line "A-A" read 2-2; and Figure? should appear as shown below instead of as shown in the patent;

F a-Z.

/ll/ .\\\\\\\\b\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ and that said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Officev Signed and sealed this l'lthday of December, A.D. 1935.

' Leslie Frazer.

(Seal) I Acting Commissioner of Patent; 

